Why Should Butter Be Cold in Laminated Dough?

Here is how lamination works: the layer of fat placed inside the dough is rolled and folded thinner and thinner, eventually forming dozens of fat films between dozens of sheets of dough. In the oven, the fat melts, the water in the dough turns to steam, and the steam pushes the sheets apart to create air pockets. In other words, what puffs up is not the fat but the steam filling the space left by the fat. If the fat has already melted on the counter, it will have been absorbed into the dough, leaving no separate film, and the steam will have no layer to push apart.

The working temperature range is narrow. The range in which butter is solid yet flexible enough to bend without breaking is about 13–18°C / 55–65°F. Below this range, the fat is hard and brittle; it breaks apart while rolling, tears the dough from inside, and leaks through any holes left behind. Above this range, it softens and starts to blend into the dough. Test the right consistency by hand: when pressed with a finger, the butter should take an indentation without sticking to the finger. Keep the dough itself at the same temperature too, or the two will behave differently. After taking the butter out of the refrigerator, shape it by placing it between 2 sheets of parchment paper and tapping it with a rolling pin; this thins the butter without warming it.

That is why working with laminated dough means returning it to the refrigerator at intervals. After each fold, wrap the dough in plastic wrap and rest it in the refrigerator for at least 30 minutes; this both firms the fat again and relaxes the gluten stretched by kneading. The work surface should be marble or a similar cool surface, and the room should be kept cool if possible. In summer, extend the wait between the two folds. Stop working and chill the dough as soon as fat begins to seep out at the edges or the dough develops a greasy shine.

The choice of fat also affects the result. Butter with less water and more fat stays pliable over a wider temperature range and breaks less while rolling. Regular butter can also be used, but it requires more frequent chilling. Margarine is easier to work with in these doughs because it stays soft over a wider range, but it does not provide the aroma of butter. Start baking in a hot oven: the steam needs to form all at once; in a lukewarm oven, the fat melts slowly and the dough spreads before it puffs. As soon as it is baked, transfer the dough from the oven to a wire rack; if it sits on the baking sheet, steam from below will moisten the layers from the inside.